1. Field of Invention
Embodiments of the present invention relate generally to electronic devices and, more specifically, in certain embodiments, to fin field-effect transistors.
2. Description of Related Art
Fin field-effect transistors (finFETs) are often built around a fin (e.g., a tall, thin semiconductive member) extending generally perpendicularly from a substrate. Typically, a gate traverses the fin by conformally running up one side of the fin over the top and down the other side of the fin. Generally, a source and a drain are located on opposite sides of the gate in the fin. In operation, a current through the fin between the source and drain is controlled by selectively energizing the gate.
Conventional finFETs are difficult to manufacture as integrated circuits. Typically, manufacturers strive to make the finFETs as small as possible either to increase the number of chips constructed per manufacturing run or to increase the functionality of each chip by increasing the number of finFETs in it. Some conventional finFETs, however, exhibit lower yields when scaled below certain sizes because it is difficult to align photolithography equipment to the small structures. This challenge is aggravated by the number of photolithography steps involved in the manufacture of some conventional devices. For instance, some finFETs are formed with three or more photolithography steps, and each step introduces another opportunity to misalign the photo-mask.